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2Water Management and Irrigation
INTRODUCTION2.1 Sustainable development and efficient manage-ment of water is an increasingly complex challenge inIndia. Increasing population, growing urbanization,and rapid industrialization combined with the needfor raising agricultural production generates compet-ing claims for water. There is a growing perception ofa sense of an impending water crisis in the country.Some manifestations of this crisis are:
There is hardly any city which receives a 24-hoursupply of drinking water.
Many rural habitations which had been coveredunder the drinking water programme are now be-ing reported as having slipped back with target datesfor completion continuously pushed back. Thereare pockets where arsenic, nitrate, and fluoride indrinking water are posing a serious health hazard.
In many parts, the groundwater table declines dueto over-exploitation imposing an increasing finan-cial burden on farmers who need to deepen theirwells and replace their pump sets and on StateGovernments whose subsidy burden for electricitysupplies rises.
Many major and medium irrigation (MMI) projectsseem to remain under execution forever as they slipfrom one plan to the other with enormous cost andtime overruns.
Owing to lack of maintenance, the capacity of theolder systems seems to be going down.
The gross irrigated area does not seem to be risingin a manner that it should be, given the investment
in irrigation. The difference between potentialcreated and area actually irrigated remains large.Unless we bridge the gap, significant increase inagricultural production will be difficult to realize.
Floods are a recurring problem in many partsof the country. Degradation of catchment areasand loss of flood plains to urban developmentand agriculture have accentuated the intensity offloods.
Water quality in our rivers and lakes is far from sat-isfactory. Water in most parts of rivers is not fit forbathing, let alone drinking. Untreated or partiallytreated sewage from towns and cities is beingdumped into the rivers.
Untreated or inadequately treated industrial efflu-ents pollute water bodies and also contaminategroundwater.
At the same time water conflicts are increasing.Apart from the traditional conflicts about waterrights between upper and lower riparians in a river,conflicts about quality of water, peoples right forrainwater harvesting in a watershed against down-stream users, industrial use of groundwater andits impact on water tables and between urban andrural users have emerged.
2.2 India with 2.4% of the worlds total area has 16%of the worlds population; but has only 4% of the totalavailable fresh water. This clearly indicates the needfor water resource development, conservation, andoptimum use. Fortunately, at a macro level India is notshort of water. The problems that seem to loom large
44 Eleventh Five Year Plan
over the sector are manageable and the challenges fac-ing it are not insurmountable.
AVAILABILITY OF WATER
WATER RESOURCES2.3 The water resource potential of the country hasbeen assessed from time to time by different agencies.The different estimates are shown in Table 2.1. It maybe seen that since 1954, the estimates have stabilizedand are within the proximity of the currently acceptedestimate of 1869 billion cubic metre (bcm) whichincludes replenishable groundwater which gets chargedon annual basis.
TABLE 2.1Estimates of Water Resources in India
Agency Estimate Deviationin from
bcm 1869 bcm
First Irrigation Commission (190203) 1443 23%Dr A.N. Khosla (1949) 1673 10%Central Water and Power Commission
(195466) 1881 +0.6%National Commission on Agriculture 1850 1%Central Water Commission (1988) 1880 +0.6%Central Water Commission (1993) 1869
UTILIZABLE WATER RESOURCES POTENTIAL2.4 Within the limitations of physiographic condi-tions, socio-political environment, legal and constitu-tional constraints, and the technology available at hand,the utilizable water resources of the country have beenassessed at 1123 bcm, of which 690 bcm is from sur-face water and 433 bcm from groundwater sources(CWC, 1993). Harnessing of 690 bcm of utilizablesurface water is possible only if matching storages arebuilt. Trans-basin transfer of water, if taken up to thefull extent as proposed under the National PerspectivePlan, would further increase the utilizable quantity byapproximately 220 bcm. The irrigation potential of thecountry has been estimated to be 139.9 MH withoutinter-basin sharing of water and 175 MH with inter-basin sharing.
2.5 While the total water resource availability in thecountry remains constant, the per capita availabilityof water has been steadily declining since 1951 due to
population growth. The twin indicators of water scar-city are per capita availability and storage. A per capitaavailability of less than 1700 cubic metres (m3) istermed as a water-stressed condition while if per capitaavailability falls below 1000 m3, it is termed as a water-scarcity condition. While on an average we may benearing the water-stressed condition, on an individualriver basin-wise situation, nine out of our 20 riverbasins with 200 million populations are alreadyfacing a water-scarcity condition. Even after construct-ing 4525 large and small dams, the per capita storagein the country is 213 m3 as against 6103 m3 in Russia,4733 m3 in Australia, 1964 m3 in the United States (US),and 1111 m3 of China. It may touch 400 m3 in Indiaonly after the completion of all the ongoing andproposed dams.
ULTIMATE IRRIGATION POTENTIAL (UIP)2.6 The demand for irrigation water in India is verylarge. However, the limits to storage and transfer ofwater restrict the potential for irrigation. UIP reassessedby the Committee constituted by the MoWR in May1997, the potential created, and the potential utilizedup to end of the Tenth Plan are given in Table 2.2.
2.7 The assessment of UIP needs to be periodicallyreviewed to account for revision in scope, technologi-cal advancement, inter-basin transfer of water, inducedrecharging of groundwater, etc. The creation of irriga-tion potential depends upon the efficiency of thesystem for delivering the water and its optimal use atthe application level. With the modern techniques ofintegrating micro irrigation with canal irrigation as hasbeen done in the case of Narmada Canal Project,Rajasthan, the UIP can further be increased. Similarlyin the case of groundwater, innovative methods ofrecharging the groundwater and also storing water inflood plains along the river banks may enhance the UIPfrom groundwater to more than 64 MH.
WATER FOR NATURE2.8 The question of a trade-off between competingclaims on water becomes most important in the con-text of ecological requirement. The National WaterPolicy (NWP) places ecology in the fourth place inthe order of priorities for water use. Yet, there is a gen-eral agreement amongst all that any water diversion
Water Management and Irrigation 45
needs to take care of river ecosystem downstream.The problem is of quantifying the Environment FlowReleases (EFR), that is the flow required for maintain-ing ecosystems. Usable water will be reduced to thatextent. During 200405, the Ministry of Environmentand Forests (MoEF) appointed a committee headedby Member, Central Water Commission (CWC), todevelop guidelines for determining the EFR. Thecommittee submitted its report in 2005. Dependingon what the final accepted recommendation is,the minimum flow required for maintaining theriver regime and environment will be decided andconsidered in water resources development and man-agement.
CLIMATE CHANGE AND UNCERTAINTY INWATER AVAILABILITY2.9 The threat of climate change is now consideredan established fact. General Circulation Models simu-late the behaviour of the atmosphere and paint whatif scenarios for various levels of greenhouse gas emis-sions. Using these models the weather experts havepredicted that global warming will intensify the hy-drologic cycle; more intense rainfall will occur in fewerspells; floods and droughts both will become moreintense; the floods will be more frequent; the rainfallwill shift towards winter; and there may be a signifi-cant reduction in the mass of glaciers, resulting in in-creased flows in the initial few decades but substantiallyreduced flows thereafter.
2.10 The MoWR has already initiated some studies inco-operation with research institutions and reputed
academic institutions to assess the impact of climatechange on water resources.
2.11 The hydrologists are yet to translate what climatechange means for the water availability, its distributionin time and space, and changes in demand. An increasein mean temperatures would increase the energyflux for evapo-transpiration. The increased potentialevapo-transpiration in the forests could trigger majorchanges in the environment, and it would result in anincreased crop water requirement in the farms. Thechanges in seasonal temperatures could change the cropseasons. Enough data is now available to paint what if scenarios for different possibilities, and to formulatesome tentative plans to respond to these possibilities.
2.12 In the post-climate change scenario, systems thatare more resilient will fare better than systems that areless resilient. Engineering infrastructure that enablesthe water managers to store and transfer water withgreater certainty can reduce the impact of uncertainty.Climate change considerations need to be factored inas we plan water resource infrastructure.
WATER REQUIREMENT2.13 The requirement of water for various sectors hasbeen assessed by the National Commission on Inte-grated Water Resources Development (NCIWRD) inthe year 2000. This requirement is based on the as-sumption that the irrigation efficiency will increase to60% from the p